Ratio of Perfluorochemical
Concentrations as a Tracer of
Atmospheric Deposition to Surface
WatersSimcikMatt F.DorweilerKelly J.2005A major question regarding the global distribution of
perfluorochemicals (PFCs) is one of transport. It has been
suggested that atmospheric transport of volatile precursor
compounds to remote areas and subsequent degradation to
the nonvolatile PFCs is responsible for contamination of
biota. This paper presents surface water PFC concentrations
aimed at identifying tracers of atmospheric sources.
Concentrations of PFCs including perfluorocarboxylates
from C<sub>6</sub> to C<sub>10</sub> and perfluorooctane sulfonate (PFOS) are
presented here from urban surface waters with presumably
both atmospheric and nonatmospheric sources of PFCs,
remote waters with only atmospheric sources of PFCs, and
Lake Michigan. Perfluoroheptanoic acid (PFHpA) and
perfluorooctanoic acid (PFOA) were detected in all surface
water samples, and PFOS was detected in all but two
samples. PFOS concentrations ranged from nondetect to
1.2 ng/L and from 2.4 to 47 ng/L in remote and urban surface
waters, respectively. PFOA concentrations ranged from
0.14 to 0.66 ng/L and from 0.45 to 19 ng/L in remote and urban
surface waters, respectively. The ratio of PFHpA to
PFOA increased with increasing distance from nonatmospheric sources suggesting that it can be used as a tracer
of atmospheric deposition of PFCs to surface waters.
The ratio ranged from 0.5 to 0.9 in urban areas and from
6 to 16 in remote areas. Applying this tracer to measurements
from Lake Michigan indicates that the primary source of
PFCs to Lake Michigan is nonatmospheric, most likely inputs
from wastewater treatment effluent.